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Fluid Level Check
Various fluids provide cooling, cleaning, lubricating, and/or sealing to vehicle components. Components of various systems take different types of fluids. The do-it-yourselfer can maintain the different systems by simply checking fluid levels and conditions. This section will guide you through correctly checking and adding fluids to vital vehicle components.

Types of Fluids
It is critical that you check the owner’s manual for the correct type of fluid that is recommended for your specific vehicle. The most common fluids that automobile owners need to check are:

  • Engine Oil
  • Transmission Fluid
  • Coolant
  • Brake Fluid
  • Clutch Fluid (Manual transmissions only)
  • Windshield Washer Fluid
  • Differential Fluid
  • Power Steering Fluid
  • Battery Electrolyte

Tech Tip
Types of Fluids
Do not add fluid to a component unless you are sure the fluid meets the specification requirements as stated in the owner’s manual. Adding incorrect fluids could void manufacturer’s warranties and lead to premature component failures.


Engine Oil
Engine oil cools, cleans, lubricates, and seals the internal engine components. Clean engine oil is gold in color, while dirty engine oil is black in color. The most common weight of engine oil is 5W30, but always refer to the your vehicle’s recommendations. To get an accurate reading it is best to check the engine oil when the engine is cold. Most automotive engines have an oil capacity between four and five quarts. Vehicle manufacturers suggest adding oil when the engine is low one quart. To check the engine oil, shut off the engine, open the hood, and look for the engine oil dipstick. The engine oil dipstick runs through a metal tube that is usually located on the side of the engine on rear-wheel drive vehicles or on the front of the engine on front-wheel drive vehicles. Refer to your owner’s manual if you have questions on the location of the engine oil dipstick. Note: When checking any fluid, it is important to park on a level surface. Pull out the dipstick, wipe it off with a shop rag, reinsert it completely into the tube, remove again, and note the reading. The engine oil should be in the safe range. To add engine oil, locate the oil filler cap on the valve cover of the engine. Use a clean funnel to add the correct amount of engine oil. Give the engine oil time to flow to the oil pan. Recheck the level and correct if necessary. Do not overfill.


Transmission Fluid
Both automatic and manual transmissions have fluid to cool, clean, lubricate, and seal internal components. Clean automatic transmission fluid is pinkish-red. The most common type of transmission fluid is Dexron/Mercon®, but always refer to the manufacturer’s recommendations. It is usually recommended to check the fluid level in an automatic transmission while it is hot. Drive the vehicle about ten minutes to warm up the transmission. To receive accurate results, most manufacturers recommend that the engine be running and that the gear selector be in park. Apply the parking brake. Locate the automatic transmission oil dipstick. With the engine idling, pull out the dipstick, wipe it off with a shop rag, reinsert it completely into the tube, remove again, and note the reading. The automatic transmission fluid should be between the full cold and the full hot marks. If low, use a clean funnel to add the necessary fluid by pouring the fluid directly into the tube. Do not overfill. It usually takes only one pint (½ quart) of fluid to bring the fluid level from the full cold to the full hot mark. Recheck the level and add more if necessary. On manual transmissions there is usually a plug on the side of the transmission. To check the fluid level, you must turn the engine off, apply the parking brake, and remove the plug with a wrench. The fluid should be at or near the bottom of the filler plug. Some manual transmissions take ATF (automatic transmission fluid), while others take heavyweight (SAE 80W90) gear oil. Check the owner’s manual for specifications. Fill as necessary. Sometimes you need a special adapter that fits on quart bottles to transfer the fluid.

Coolant
Coolant (antifreeze) comes in various colors: green, orange, red, pink, yellow, and bluish-green. The most common colors are green and orange. The standard antifreeze used in vehicles before 1995 was green in color. In 1995, General Motors started using an extended life coolant, called Dex-Cool, in their engines. Dex-Cool, orange in color, was originally manufactured by Havoline for General Motors. Today, several other coolant manufacturers produce extended life coolants. Both standard (green) antifreeze and Dex-Cool (orange) antifreeze are glycol based. The main difference between the two types of antifreeze is in the rust inhibitors and additives. Ethylene glycol, which is used in standard and extended life coolants, is a toxic substance. When checking coolant level, the engine must be cool. First, check the level in the coolant recovery tank. The recovery tank is usually translucent with a “full cold” and a “full hot” mark. If adding, remove the cap and add a 50% water to 50% antifreeze mixture. Second, check the level in the radiator. This requires removing a cool radiator cap and looking into the radiator. Warning: Never remove a hot radiator cap – severe burns could result. The fluid should be at or near the top. Add a 50/50 mixture as needed. Reinstall the cap.

Tech Tip
Environmentally Friendly Coolant
Ethylene glycol based coolants are toxic and can be fatal to animals if ingested. Some coolant manufacturers are formulating more environmentally friendly coolants. Antifreezes that are propylene glycol based are safer in case of spills or accidental ingestion.


Brake Fluid
Brake fluid provides the transfer of hydraulic pressure to the wheels. Clean brake fluid is clear in color. Use extreme caution when handling. Brake fluid is harmful to your eyes and can damage a vehicle’s finish. The most common type of brake fluid is DOT 3, but always refer to your manufacturer’s recommendations. The brake master cylinder that houses the fluid is usually mounted on the driver’s side firewall in the engine compartment. Most vehicles today have a plastic translucent reservoir with a “min” and “max” line. To add brake fluid, park on a level surface, turn the engine off, remove the cap, and add as necessary. When reinstalling the cap, make sure that the rubber gasket seats properly.

Clutch Fluid
Vehicles that have manual transmissions with hydraulic clutches have a clutch master fluid reservoir. It is usually mounted next to the brake master cylinder. Clutch fluid is commonly DOT 3 brake fluid, but always check your owner’s manual. To check the clutch fluid, turn the engine off and look through the translucent reservoir. It should be at or near the top. To add clutch fluid, park on a level surface, turn off the engine, remove the cap, and add as necessary. When reinstalling the cap, make sure that the rubber gasket seats properly.

Windshield Washer Fluid
Windshield washer fluid is usually blue in color. It is specially formulated so it does not freeze. Never use cooling system antifreeze as it is not made for window cleaning and can damage the vehicle’s finish. Do not confuse this reservoir with the overflow antifreeze reservoir – they often look similar. The cap on a windshield washer reservoir usually has a wiper symbol engraved on it. To add windshield washer fluid, locate the cap and fill until the fluid is about half an inch from the top. When adding windshield washer fluid, take a moment to inspect the windshield wipers. The wipers should be soft and without cracks. If the wipers are streaking or skipping across the windshield they need replacing. You can replace just the rubber insert or the complete blade. Follow instructions that come with the replacement parts for specific assembly procedures.

Differential Fluid
Rear and front differentials, which connect the drive shafts to the wheels, also require fluid. This fluid check is required on rear-wheel drive or four-wheel drive vehicles, and is similar to checking manual transmission fluid. Remove the check plug, check the level, and fill as necessary. The oil should be at the bottom of the plug hole. Gear oil (SAE 80W90) is the most common differential fluid. Some differentials use limited slip additives. Always check your owner’s manual for the specific fluid.

Power Steering Fluid
Most vehicles today have power steering. The power steering pump is located off an engine drive belt. The cap and the dipstick are commonly one unit. To check the fluid, shut off the engine, locate the power steering reservoir, remove the dipstick, wipe it off, reinstall, remove again, and note the reading. The stick usually has a full hot and a full cold line. Using a clean funnel, add fluid as necessary. Power steering fluid can be clear, gold, or red. Check your owner’s manual for specifications.

Battery Electrolyte
The electrolyte in a battery is a mixture of sulfuric acid and distilled water. Over time, some of the water may evaporate. To check the level, put on safety goggles and gloves, remove your rings and watches, disconnect the negative battery cable, and remove the cell caps. On some vehicles the batteries are sealed and cannot be opened. Refer to your owner’s manual to see if your battery is considered maintenance free. Usually there is a split ring indicator in each cell to indicate the correct levels. If the fluid is low, add only distilled water. Do not overfill. Replace the caps and reattach the negative battery cable. Warning: Wash your hands thoroughly to remove any battery acid.

Summary
Fluids in the automobile have critical functions. Fluids that are neglected and run low for long periods of time add stress to the various components and can cause premature damage. Practice preventative maintenance by checking fluid levels frequently. Always refer to your owner’s manual to identify the correct type of fluid for your specific vehicle. Using incorrect fluids can harm vital systems and could cause a hazardous situation while driving. Most of the fluids used in automobiles are toxic. Antifreeze has a sweet taste to animals and can be fatal if ingested. Dispose of all fluids properly. Always wash your hands thoroughly after checking and adding fluids.

Trouble Guide - Leaking Fluids
Most fluids have distinct colors. Use this to your advantage. If you see your vehicle leaving a leak on the ground, note its color, texture, and position under the vehicle. This may lead you to the component that is failing.



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